Abnormal Electrocardiogram

Abnormal Electrocardiogram (ECG)

Overview

An abnormal electrocardiogram (ECG) indicates deviations from normal cardiac electrical activity. Abnormal findings may reflect benign variations or serious cardiac conditions. Common abnormalities include:

• Arrhythmias (atrial fibrillation, atrial flutter, ventricular tachycardia).

• Ischemic changes (ST elevation, ST depression, T-wave inversion).

• Conduction defects (bundle branch block, AV block).

• Chamber enlargement (left atrial/ventricular hypertrophy).

• Electrolyte disturbances (hyperkalemia, hypokalemia, hypocalcemia).

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Treatment Options

(Management depends on the underlying abnormality detected on ECG)

1. Arrhythmias

• Atrial fibrillation (AF):

  • Rate control:

    • Metoprolol tartrate: 25–50 mg PO BID, titrate to HR < 110 bpm.

    • Diltiazem: 120–360 mg/day PO in divided doses.

  • Anticoagulation (stroke prevention):

    • Apixaban: 5 mg PO BID (reduce to 2.5 mg BID if elderly/low weight/renal impairment).

    • Warfarin: dose adjusted to INR 2–3.

• Ventricular tachycardia (stable):

  • Amiodarone: 150 mg IV bolus over 10 min, then 1 mg/min infusion for 6 hrs.

• Bradyarrhythmias/AV block:

  • Atropine: 0.5 mg IV every 3–5 min as needed (max 3 mg).

  • Temporary/permanent pacemaker if persistent.

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2. Ischemic Changes (Acute Coronary Syndrome)

• Immediate therapy:

  • Aspirin: 160–325 mg PO chewed.

  • Clopidogrel: 300–600 mg PO loading dose.

  • Nitroglycerin: 0.3–0.6 mg sublingual every 5 min (max 3 doses).

  • Morphine: 2–4 mg IV PRN for pain.

• Long-term therapy:

  • Beta-blockers (e.g., metoprolol 25–50 mg PO BID).

  • ACE inhibitors (e.g., ramipril 2.5–5 mg PO BID).

  • Statins (e.g., atorvastatin 40–80 mg PO daily).

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3. Conduction Abnormalities

• Bundle branch block: often managed by treating underlying cause.

• Complete heart block:

  • Temporary pacing acutely.

  • Permanent pacemaker for chronic cases.

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4. Electrolyte Abnormalities

• Hyperkalemia (peaked T-waves, widened QRS):

  • Calcium gluconate: 10 mL of 10% IV over 2–5 min.

  • Insulin + glucose: Regular insulin 10 units IV + 25–50 g glucose IV.

  • Sodium polystyrene sulfonate or hemodialysis if severe.

• Hypokalemia (flattened T-waves, U-waves):

  • Potassium chloride: 20–40 mEq PO/IV, not exceeding 10 mEq/hr IV infusion.

• Hypocalcemia (QT prolongation):

  • Calcium gluconate: 10 mL of 10% IV over 10 min.

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Supportive & Monitoring Measures

• Continuous cardiac monitoring in acute/unstable patients.

• Correct precipitating factors: medications, thyroid disease, hypoxia, infection.

• Repeat ECGs to track evolution of abnormalities.

• Lifestyle management in chronic conditions: smoking cessation, weight control, diet, exercise.

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Key Notes

• Not all abnormal ECGs are pathologic; some may be normal variants.

• Urgency depends on symptoms: chest pain, syncope, hypotension, or hemodynamic instability → emergency management.

• Always interpret ECG in the context of history, clinical exam, and labs.